Add shutDown to ConfigPlugin

Remove config button from navbar on shutdown

Signed-off-by: Tomas Slusny <slusnucky@gmail.com>

runelite-client/src/main/java/net/runelite/client/plugins/config/ConfigPlugin.java

@@ -56,4 +56,10 @@ public class ConfigPlugin extends Plugin
 
 		ui.getPluginToolbar().addNavigation(navButton);
 	}
+
+	@Override
+	protected void shutDown() throws Exception
+	{
+		ui.getPluginToolbar().removeNavigation(navButton);
+	}
 }